The problem for me was trying by email to show that, instead of me trying to demonstrate every possible variation on a chord - which is what the (foreign) correspondent wanted - it might be of more value for him to (a) understand what notes make up any chord (b) know where those notes are on the fretboard. DIY chords.

Alas, (a) was a non-starter. It might have been easier for us face-to-face, but an obvious impossibility for this person to understand what I was attempting to say...

As I said earlier, in the end I just gave up and said, "Buy a book of chords and learn them".